In the supply of electricity to certain electrical devices it is often necessary for the cable or flex used to withstand an initial high electrical voltage which is used to commence operation of the device, which thereafter runs on a standard mains voltage. For example, in order to strike a mercury vapour lamp or other similar lighting means, it is necessary to supply an initial voltage of approximately 4,500 volts. If a standard 3-core 13 amp electrical cable is used to supply this voltage, the cable can cope initially but quickly becomes burnt out with repeated use. There is also a significantly increased risk of fire.
To overcome the problem of supplying an initial high voltage to devices, such as lamps, which then run on a standard mains voltage, a heavy gauge single core insulated cable is often used as the live wire of the electrical supply along with separate standard single core neutral and earth wires. When wiring such a device to a mains electric supply these three wires are often pulled into a hollow sheath or tubular casing by the electrician so that the resulting single flex can be threaded, as appropriate, down a conduit between the electrical supply and the location of the device. However, it will be appreciated that this considerably increases the work required by the electrician as compared with the wiring of a device capable of being supplied by a standard 3-core cable. In addition, the sheathing of the three separate wires in the outer casing is often difficult to accomplish satisfactorily as the casing tends to twist and wrinkle.
The object of the present invention is to overcome or substantially mitigate the aforementioned problems.